Control operating means



1960 E. c. PINSENSCHAUM 2,957,057

CONTROL OPERATING MEANS 2 Sheets-Sheet 1 Filed Dec. 3, 1958 INVENTOR. EDWIN C. PINSENSCHA UM l "IIIIIIII Oct. 18, 1960 E. c. PINSENSCHAUM 5 5 CONTROL OPERATING MEANS 2 Sheets-Sheet 2 Filed Dec. 3, 1958 7 'III' INVENTOR. EDWIN C. PINSENSCHAUM 2,957,057 Patented Oct. 18, 1960 CONTROL OPERATING MEAN Edwin C. Pinsenschaum, Columbus, Ohio, assignor to American Brake Shoe Company, New York, N.Y., a corporation of Delaware Filed Dec. 3, 1958, Ser. No. 777,912

7 Claims. (Cl. 200-) This invention relates to mechanisms for operating a pair of control devices each of which is movable between two positions or conditions.

The main object of the invention is to provide mechanism including independently operatable means such as push buttons for operating a pair of control devices such as electric switches from first positions to second positions and means by which the control devices are permitted or caused to remain in the second positions until both push buttons are released.

it is another object of the invention to provide mechanism as set forth in the foregoing object which may be used with facility for operating control devices of machine tools and which may provide a protective device for the operator thereof in that it requires the operator to use both hands to initiate each cycle of operation of the machine tool.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the accompanying drawings:

Fig. 1 is a side view in elevation of a hydraulic press to which control operating mechanism including this invention has been applied, parts of this mechanism being shown in dotted lines;

Fig. 2 is a view in section on an enlarged scale, the section being taken on line 22 of Fig. 1, showing the control mechanism seen in Fig. 1 in elevation;

Figs. 3 and 4 are views on a larger scale showing the details of the structure of the press, Fig. 3 showing the push button released and Fig. 4 showing the push button depressed, and

Fig. 5 is a diagrammatic view of the control operating mechanism shown in Figs. 1 through 4 of the drawings incorporated into the electric control circuit of the press.

Mechanisms which include the present invention may be used with facility as operator protecting devices on machine tools and for the most part probably will be used as such. It is to be understood, however, that the invention may also be employed for other control operating purposes in manners that are readily apparent to those skilled in the art. Since, in one of its aspects, the invention may be considered as a protective type control operating device it is described and illustrated herein as such in connection with a hydraulic press.

Fig. 1 of the drawings shows a hydraulic press to which mechanism including the features of the invention has been applied. This press has a hollow cast open gap or 6 type frame 10 which includes an upright portion 11, a forwardly projecting top or head portion 12 and a forwardly projecting bed or platen portion 13 which is directly below and aligned with the head portion 12. The head portion 12 of frame 10 contains a reciprocating ram type hydraulic motor, not shown, the ram of which extends through the bottom wall of the head portion 12 and is movable toward and away from the bed or platen portion 13 of frame 10. The hydraulic motor of which ram 14 forms a part is driven or operated by a hydraulic system which is also contained within the frame 10 and the pump of which is driven by an electric motor 15' which is shown diagrammatically in Fig. 5 of the drawings.

The hydraulic system of this particular press is not shown herein and it suflices to say of it that it includes an automatic pressure differential operated valve mechanism which is under the control of a solenoid operated valve 16 (Fig. 5), the solenoid of which must be energized at least momentarily to cause the pressure differential valve mechanism to be conditioned to initiate the operation of the ram, that is, to cause the ram 14 to begin its working stroke in which it moves downwardly toward the press bed or platen 13, or work thereon, at a high rate of speed. The circuit is also such that the ram, upon reaching the end of its downward or working stroke or upon engaging work will exert a predetermined pressing pressure on the work, and if the coil of solenoid valve 16 has been de-energized, then to return to its original up or idle position as seen in Fig. 1 of the drawings. If the coil of solenoid valve 16 is not deenergized when the ram has completed its downward or working stroke the ram will dwell upon the work and will remain in this condition until the coil of the solenoid valve 16 is de-energized.

The above-described press and the hydraulic circuit thereof are fully described in an application Serial No. 559,438 filed January 16, 1956, by Robert Smilges for a Hydraulic Press and Control Means to which reference should be made for a complete understanding of its details.

In Fig. 5 of the drawings, the solenoid valve 16 is shown in an electric circuit which includes two control means in the form of two position or off-on type electric switches 17 and 18 which will be described in detail hereinafter.

The bed or platen portion 13 of the press frame 10 is provided with a pair of aligned rectangular openings, one in each of its opposite side walls, and the switches 17 and 18 are mounted in these openings by control means in the form of manually operated push button assemblies 19 and 20, respectively, which also serve to close the openings. As best seen in Figs. 3 and 4 of the drawings, each of the push button assemblies includes a rectangular base plate 21 having a rectangular bifurcated arm 22 pressed from the center thereof to provide a support for one of the switches and a central rectangular opening 23 through the base plate 21. The assembly also in cludes a flexible rectangular diaphragm 24 and a rectangular rim or frame 25 which covers the diaphragm 24 and abuts the base plate 21 adjacent its peripheral edge. Screws 26 which extend through the rim or frame 25, the diaphragm 24' and base plate 21 into tapped holes in the press frame secure the push button assembly over the opening in the side wall of the press frame and the arm 22 of the base plate extends into the opening so that the switch carried thereby is held Within and protected by the frame 10.

The diaphragm 24 is molded to include a thin flexible, resilient off-set center portion to which there is attached a metal stiffening plate 27' which is provided with a central opening through which part of the material which forms the flexible diaphragm extends to form a switch operating pad 28 and the switch is mounted upon the arm 22 in such manner that one of its operating elements or buttons 29 will be engaged by the pad 28 when the diaphragm is depressed.

The control operating apparatus also includes a pair of identical bellcrank levers 30 which are contained within or housed by the bed or platen portion 13 of the press frame 10. Each of these bellcrank levers 30 is pivotally mounted to the frame It by a pivot 31 and each includes a pair of arms 32 and 33 which extend substantially at'n'ght angles with respect to one another. The ends of the arms 32 of each lever 30 are joggled as at 34 and bifurcated to provide a slot 35 and these arms overlap each other and are interconnected by a spool 36 contained in the slots 35 of both arms 32 so that motion of one of the bellcrank levers 30 will be imparted to the other in an opposite direction.

The ends of the arms 33 extend through and are carried and guided by slots in the'ends of the arms 22 of the base plate 21 of the push button assemblies 19 and 20 and each is provided witha finger 37 which extends at one side of the switches 17 and 18 and engages the stiffening plate 27 of the diaphragm 24. These fingers '37 are normally held in engagement with the plates 27 by a spring 38 which is attached to two cars or lugs 39, one on each of the arms 32. The ends of the arms 33 are also each provided with an abutment 40 adjacent the finger 37 which engages a second operating button 41 of one of the switches 17 or 18.

From the foregoing description, it is obvious that the spring 38 urges the levers 30 to rotate in opposite directions which are such that the abutments 40 thereof engage and operate the buttons 41 of the switches 17 and 18 and that whenever the diaphragm 24 of either push button assembly 19 or Zll is depressed that it will move the levers 30 together and away from the switch buttons 41 thereby permitting the pads 28 of the diaphragms 24 to operate the switch buttons 29.

Referring now to Fig. of the drawings wherein the above described control operating means is shown in connection with the previously mentioned electric circuit of the press, electric current is supplied to the electric motor 15 of the press over two main lead lines 42 and 43 which receive current from a suitable source, not shown, and in which there is a main switch 44. A line 45 connected to the main line'43 on the motor side of main switch 44 leads to one contact of the switch 18 and from the other contact of this switch a line 46 leads to one contact of the switch 17. The other contact of switch 17 is connected by a lead line 47 to one terminal of the solenoid coil of solenoid valve 16 and the other terminal of this coil is connected through a lead line 48 to the main line 42 between the motor 15 and main switch 44. Fuses 49 and 50 are included in the lead lines 45 and 48, respectively.

they must be opened before the ram 14 develops its full operating tonnage upon the work in order that the ram may begin to return to its up position as soon as the full operating tonnage of the ram has been attained, but that merely by holding one of the diaphragms 24 in its depressed condition that the ram 14 can be caused to dwell upon the work and then return to its up position by releasing the diaphragm.

It will also be seen that as an operator protecting device the invention is particularly adapted for use with high speed machinery wherein that operation which would be particularly dangerous to the operators hands, for ex- 1 ample, will be completed before the operator can release The electric control switches 17 and 18 are, as indicated in the drawing, two position toggle type switches, that is, they are toggle switches which may be actuated by their buttons 29 to closed positions and by their buttons 41 to open positions and they will remain in either of these positions until they are shifted therefrom by either of their buttons 29 or 41. These switches are normally actuated to their open positions by the action of the linkage including the spring 38 and levers 30.

When it is desired to cause the press to begin a cycle of operation the solenoid coil of valve 16 must be energized at least momentarily, and to accomplish this both of the diaphragms 24 must be depressed. Depression of the diaphragms 24 first moves the levers 30 and their abutments 40 away from the switch buttons 41 and then the pads 28 of the diaphragms 24 actuate the switches 17 and 18 to cause them to move to their closed positions in which the solenoid coil will be energized and the ram 14 will commence its downward or working stroke. Since the switches 17 and 18 are two position switches and must be actuated mechanically from one position to another, if only one of the diaphragms is released the mechanical linkage can not cause its switch to return to its open position since the linkage is held away from the switch button 41 by the other diaphragm 24.

From the foregoing description, it will be obvious that to initiate a fully automatic cycle of operation of the press ram that the switches 17 and 18 must first be closed and either of the diaphragms and place his hand or hands in the danger area of the machine. In the press illustrated the operator must employ both of his hands to depress the diaphragms 24 and the press ram travels to and engages the work at a speed such that the operator'can not move his hand or hands from the diaphragms 24 to underneath the ram.

It will also be seen that the invention requires both diaphragms 24 to be depressed to initiate a cycle of operation of the press and that both diaphragms must be released before the cycle can be completed and/ or repeated. This guarantees that an operator of the press can not tie down or hold one diaphragm 24 continuously depressed and cause repeated operation of the press merely by operating the other diaphragm.

It will be understood by those skilled in the art that while the invention is herein specifically described as a sequence device for protecting the hands of an operator of a machine tool that the invention can be used with facility as a sequence device for controlling other operations of a machine tool and that the diaphragms 24 may find their full equivalents in mechanically operated devices and that the switches 17 and 18 may find their full equivalents in other devices such, for example, as two position valves.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming'within the scope of the claims which follow:

I claim:

1. Apparatus for operating a pair of control means each of which is movable to two positions, said apparatus including a pair of independently operated means for moving said control means from the first to the second of said positions; mechanism for returning said control means to the first of said positions, and means operated by either of said independently operated means rendering said mechanism inoperative to return either of said control means to said first positions whereby both of said independently operated means must be operated to move said control means from said first to said second positions and only one of said independently operated means need be maintained in its operating position to prevent said mechanism fromreturning said control means to said first positions.

l fhpparatus for operating a pair of control means each of which is movable to two positions, said apparatus including a pair of independently operated means for moving said control means individually from the first to the second of said positions; mechanism for returning said control means to the first of said positions, said mechanism including a pair of movable elements; means interconnecting said movable elements whereby movement of one is imparted to the other; resilient means causing said mechanism to return said control means to said first position, and means operated by either of said independently operated means for rendering said mechanism inoperative to return said control means to said first position whereby both of said independently operated means must be operated to move said control means from said first to said second-positions and only one of said independently operated means'need be maintained in its operating position toprevent said mechanism from returning said control means to said first positions.

3. Apparatus for operating a pair of control means each of which is movable to two positions, said apparatus including a pair of manually operated push button means for moving said control means from the first to the second of said positions; mechanism for returning said control means to the first of said positions, and means operated by either of said push button means rendering said mechanism inoperative to return either of said control means to said first positions whereby both of said push button means must be operated to move said control means from said first to said second positions and only one of said push button means need be maintained in its operating position to prevent said mechanism from returning said control means to said first positions.

4. Apparatus for operating a pair of control means each of which is movable to two positions, said apparatus including a pair of independently operated means for moving said control means individually from the first to the second of said positions; mechanism for returning said control means to the first of said positions, said mechanism including a pair of levers; pivot means mounting said levers; means interconnecting said levers whereby movement of one is imparted to the other; resilient means causing said mechanism to return said control means to said first position, and means operated by either of said independently operated means for rendering said mechanism inoperative to return said control means to said first position whereby both of said independently operated means must be operated to move said control means from said first to said second positions and only one of said independently operated means need be maintained in its operating position to prevent said mechanism from returning said control means to said first positions.

5. Apparatus for operating a pair of control means each of which is movable to two positions, said apparatus including a pair of manually operated push button means for moving said control means from the first to the second of said positions; mechanism for returning said control means to the first of said positions, said mechanism including a pair of movable elements; means interconnecting said movable elements whereby movement of one is imparted to the other; resilient means causing said mechanism to return said control means to said first position, and means operated by either of said push button means for rendering said mechanism inoperative to return said control means to said first position whereby both of said push button means must be operated to move said control means from said first to said second positions and only one of said push button means need be maintained in its operating position to prevent said mechanism from returning said control means to said first positions.

6. Apparatus for operating a pair of control means each of which is movable to two positions, said apparatus including a pair of manually operated push button means for moving said control means from the first to the second of said positions; mechanism for returning said control means to the first of said positions, said mechanism including a pair of bellcrank levers; pivot means mounting said levers; means interconnecting one arm of each of bellcrank levers whereby movement of one is imparted to the other; resilient means causing said mechanism to return said control means to said first position, and means operated by either of said push button means for rendering said mechanism inoperative to return said control means to said first position whereby both of said push button means must be operated to move said control means from said first to said second positions and only one of said push button means need be maintained in its operating position to prevent said mechanism from returning said control means to said first positions.

7. In a press including a pair of spaced electric control switches each of which is independently movable from a first position to a second position, a pair of manually operated push button means for moving said switches from said first position to said second position; a pair of bellcrank levers for moving said switches from said second position to said first position; pivot means mounting said bellcrank levers; means interconnecting one arm of each of said levers whereby movement of one of said bellcranl: levers imparts movement to the other in an op posite direction; spring means causing said levers to return said switch means to said first position, and means on the other arm of each of said bellcrank levers op erated by said push button means for rendering said bellcrank levers inoperative to return said switches to said first position whereby both of said push button means must be operated to move said switch means to said sec ond position and only one of said push button means need be maintained in its operating position to prevent said bellcrank levers from returning said swithces to sai first position.

References Cited in the file of this patent UNITED STATES PATENTS 1,440,894 Robin Jan. 2, 1923 1,715,180 Zeh May 28, 1929 2,171,529 Baldwin et a1 Sept. 5, 1939 

